President Barack Obama on Tuesday sat with the leaders of China, India, Russia and top officials from nearly 50 other countries to try to reduce the threat of nuclear terrorism at the Nuclear Security Summit in Seoul, South Korea.

The conference, overshadowed by concerns about North Korea's nuclear and ballistic missile activities, shied away from expanding its mandate to call for concrete steps toward ridding the world of atomic weapons.

But host South Korea defended the summit, saying it did “yield practical outcomes to reduce the threat of nuclear terrorism.” Analysts, however, describe the actual results modest and note that nothing binding was adopted.

Italy pledged to rid itself of all fissile material. The United States joined Belgium, France and the Netherlands in a deal to begin producing, four years from now, medical isotopes without the use of highly enriched uranium.

Several countries agreed to switch to low enriched uranium, which cannot be weaponized, to fuel research reactors.

But beyond that, there are few outcomes contributing to the summit's goal of securing vulnerable nuclear materials around the world.

The communique issued at the end of the summit does not mention North Korea nor Iran -- two countries are at the forefront of current concerns when it comes to suspected development of nuclear weapons.

With a North Korean launch of a ballistic missile likely just weeks away, President Obama and his counterparts discussed on the summit sidelines how to respond if Pyongyang goes ahead with what it contends will be a peaceful space launch.

While North Korea was not on the agenda, the summit's participants did effectively speak with one voice regarding Pyongyang, South Korea's Unification Minister Yu Woo-ik said.

Yu, who coordinates Seoul's policy towards North Korea, said the leaders attending the summit clearly articulated requests for Pyongyang to drop its plan for the mid-April launch.

The summit's host, South Korean President Lee Myung-bak, said it is inappropriate for the North to pursue such projects while its own people have so little. The launch, he said, will only further isolate Pyongyang from the international community.

North Korea's foreign ministry, in a statement Tuesday, defended its planned launch, contending it should not be seen as a violation of sanctions forbidding it from the use of ballistic missile technology.

Pyongyang's statement said it “will never give up the satellite launch,” and that what it called "a peaceful activity" is a legitimate right of a sovereign state and essential for North Korea's economic development.

The impoverished and isolated country has twice before failed to place a satellite into orbit.